Having burst onto the music scene in 2002 as a contestant on Pop Idol: The Rivals, Sarah - along with Nadine Coyle, Nicola Roberts, Cheryl Tweedy and Kimberley Walsh - formed the chart topping band Girls Aloud.

"I just went mental. It took a couple of weeks to sink in and I went off the rails really badly,” she continued.

The star revealed that she had also been hooked on sleeping pills - with rehab helping her break her dependancy.

"Rehab was a depressing place to be with a lot of troubled people. I came off Zopiclone. I started taking them four years ago and coming off them was horrible. It took three weeks in rehab to start sleeping normally again,” she said.

Her experience in rehab helped Sarah learn about her own limits - and she later said in an interview with Now Magazine that she had not quit alcohol altogether.

“I’m eating really healthily and whilst I never said that I would be teetotal – and I do still enjoy a glass of wine socially with dinner or when I’m out friends – I have reined it right in,” she said in 2012.

"The treatment I’ve had has helped me see that being destructive is not the answer. I am very careful about when I drink and what my mood is like because I’ve learned so much about alcohol and depression,” she added.

An interview with Hello! the same year saw Sarah reflect on her lowest point before checking into rehab, and again the star insisted she was in control of her own drinking after treatment.

Sarah has opened up about her wild partying in the past (Image: Getty Images Europe)

The star has said she learned to 'reign in' her drinking after undergoing treatement in rehab (Image: Manchester Evening News)

"I’ve been told by those close to me that was when I hit my worst… I was crying hysterically. I felt ashamed, embarrassed, terrified – my emotions were all over the place,” she said.

“I’ve turned 30 now and, although there will always be a bit of the rock chick in me, I’m trying to embrace my softer and more feminine side. I’ve realised I can socialise without booze,” she added.